Effective Lifetime Research Articles

Tuning oxygen vacancies in vanadium-doped molybdenum oxide for silicon solar cells with hole selective contact

Near stoichiometric molybdenum oxide (MoO3-x) film has attracted extensive interest as superior hole-selecting material in optoelectronic devices. However, the existence of multi-oxidation states significantly affects its work function and carrier transport behaviors. In this work, we have proposed a facile way to modulate the oxidation states of solution-processed MoO3-x with vanadium ions (V5+) doping (MoO3-x:V), beneficial for improved hole-selecting contact performance with silicon. As the doping concentration of V5+ increases, oxygen vacancies and reduced Mo5+ ions reduce, resulting in the increase of work function of MoO3-x film. The effective carrier lifetime of MoO3-x deposited Czochralski silicon has been largely improved from 60.1 to 153.0 μs (Δn = 1015 cm−3) at the optimized doping concentration of 5%, and the contact resistivity is reduced from 9.1 to 2.1 Ω cm2 simultaneously. The finished solar cells with the scheme of Ag/MoO3-x:V/n-Si have exhibited significantly improved conversion efficiency. Our results have demonstrated a very promising way to modulate the stoichiometry and work function of MoO3-x film, which has great potential in solar cell and light emitting diode applications.

Effect of mineral fertilisers application on the transfer of natural radionuclides from soil to radish (Raphanus sativus L.)

Non-controlled usage of mineral fertilisers in agriculture land of Kazakhstan is a concerning issue, due to possible contamination of the soil by radionuclides. Pot experiment of growing of R. sativus with application of mineral fertilisers was carried out under natural conditions. Two commonly used mineral fertilisers, mono-potassium phosphate and ammonium nitrate, were chosen in the frame of current research to determine the impact of mineral fertiliser on transfer of natural radionuclides from soil to R. sativus edible part. For this goal, the activity concentrations of natural radionuclides U-234, U-238, Th-230, Th-232 and Ra-226, were determined in both R. sativus edible part and the investigated soil by using alpha-particle spectrometry. The highest activity concentrations were found for R. sativus edible part growing on soil that was fertilised by mono-potassium phosphate and were equal to 174 ± 17, 134 ± 15, 62 ± 4, 15 ± 2 and 2.8 ± 0.6 Bq/kg for U-234, U-238, Th-230, Th-232 and Ra-226, respectively. The results of soil-to- R. sativus edible part transfer factor for different radionuclides varied depending on the mineral fertiliser used. For evaluation of impact during consumption of R. sativus edible part by a population of Kazakhstan, annual effective ingestion dose and excess lifetime cancer risk were determined. The highest annual effective ingestion dose was found for R. sativus edible part cultivated in mono-potassium phosphate-fertilised soil and was equal to 4.4 μSv year−1.

Photoelectrochemical Antibacterial Platform Based on Rationally Designed Black TiO2-x Nanowires for Efficient Inactivation against Bacteria.

A hyphenated strategy for photoelectrochemical (PEC) disinfection is proposed with rationally designed black TiO2-x as a photoresponsive material. The PEC method, a fusion of electrochemistry and photocatalysis, is an innovative and effective way to improve photocatalytic performance, which imparts certain properties to the photoelectrode and greatly promotes the charge transfer, thus effectively inhibiting the recombination of carriers and greatly promoting the catalytic efficiency. The oxygen vacancy (Vo) engineering on TiO2 is conducted to obtain black TiO2-x, which shows a much larger light absorption region in the full solar spectrum than the pristine white TiO2 and presents excellent PEC sterilization performance. The bactericidal efficiency with the PEC method is 10 times higher than that with the photocatalytic method, inactivating 99% of bacteria within a short time of 30 min. In addition, the black titanium oxide nanowires (B-TiO2-x NWs) are grown on flexible carbon cloth (CC) to form a sandwich structural self-cleaning face mask. The bacteria adhering to the surface of the mask will be sterilized quickly and efficiently under the illumination of visible light. The face mask with the characteristics of superior antibacterial effect and long service lifetime will be used for epidemic prevention and reduce the second pollution.

Accelerated reliability tests of n+ and p+ poly-Si passivated contacts

We report on the stability of encapsulated, low-pressure chemical vapor-deposited phosphorus ( n + poly-Si) doped and boron ( p + poly-Si) doped poly-Si/SiO x passivated contacts by exposing the samples to three different accelerated tests: damp heat test, thermal cycling and ultraviolet exposure, adhering closely to the IEC 61215 standard. Outdoor testing was also performed by exposing the samples in the outdoor testing field at the National Renewable Energy Laboratory, and preliminary data accumulated for 1000 h from February to April of 2021 is reported. We studied non-metallized, thermally-metallized, and screen-printed n + and p + poly-Si by monitoring the effective minority carrier lifetime at the implied maximum power point using a Sinton lifetime tester, and recorded photoluminescence images before and after the exposure. The samples were found to be stable under all test conditions, which is encouraging for incorporation of these contacts in next-generation industrial silicon solar cells. • Three accelerated tests performed on encapsulated LPCVD n + and p + poly-Si/SiO x , adhering closely to IEC 61215 standard. • Samples include non-metallized, thermally metallized, and screen-printed n + and p + poly-Si/SiO x . • Effective minority carrier lifetime and PL images of the sample monitored. • All samples found to be stable after the exposure to accelerated and outdoor tests.

Waveguide-Mode-Enhanced Millimeter-Wave Photomodulators

The modulation of millimeter-wave transmission through a silicon wafer upon photoexcitation is typically very inefficient for off-the-shelf low effective charge carrier lifetime wafers, typically requiring tens of kilowatts of photoexciting intensity to generate significant modulation. Here we demonstrate that increasing the light-matter interaction for the millimeter waves using diffractively coupled waveguide modes leads to an increase in photomodulation efficiency of greater than two orders of magnitude, while maintaining the switching speed, of the order of $10\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{s}$, of the bare wafer.

Investigating the degradation behaviours of n+-doped Poly-Si passivation layers: An outlook on long-term stability and accelerated recovery

In this article, we study the kinetics of firing-activated degradation and recovery of industrially processed n + -doped poly-Si on thin oxide passivation layers subjected to illuminated annealing at elevated temperatures. The impact of a comprehensive range of fast-firing conditions on the subsequent degradation and recovery were assessed. The results indicate that the recovery process is dependent on the peak firing temperature, where higher temperatures led to an improvement in effective lifetime of up to 20% compared to the pre-fired state, and a very low surface dark saturation current density of 2.9 fA/cm 2 . By cycling through light soaking and dark anneal conditions, we show that unlike the commonly studied boron-oxygen light-induced degradation (BO-LID) and light- and elevated temperature-induced degradation (LeTID), this newly observed instability in n + -doped poly-Si passivation layers is not reversible, that is, once a degradation/recovery cycle is completed, the lifetime remains very stable under subsequent light soaking. This indicates that the surface related instability may be able to be completely resolved following the completion of the first degradation/recovery cycle. With this in mind, we investigate the potential for high intensity laser illumination (up to 150 kW/m 2 ) to rapidly increase the recovery rates, however, this does not seem sufficient to cycle through degradation and recovery on a timescale that is amenable with mass production. The mitigation of any potential instabilities at the poly-Si interface has significant implications for the reliability of n-type tunneling oxide passivated contact (TOPCon) solar cells. • Firing conditions have a significant impact in stability of polysilicon passivation. • The firing-induced surface instability is different to previous degradation modes. • Cycling between degraded and recovered states does not occur.

Predicting Solar Cell Performance from Terahertz and Microwave Spectroscopy

AbstractMobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current‐voltage characteristics of a solar cell from such measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter‐laboratory variations are discussed using a (Cs,FA,MA)Pb(I,Br)3 halide perovskite thin‐film as a case study. At 1 sun equivalent excitation, neither transport nor recombination is significantly affected by exciton formation or trapping. Terahertz, microwave, and photoluminescence transients for the neat material yield consistent effective lifetimes implying a resistance‐free JV‐curve with a potential power conversion efficiency of 24.6 %. For grainsizes above ≈20 nm, intra‐grain charge transport is characterized by terahertz sum mobilities of ≈32 cm2 V−1 s−1. Drift‐diffusion simulations indicate that these intra‐grain mobilities can slightly reduce the fill factor of perovskite solar cells to 0.82, in accordance with the best‐realized devices in the literature. Beyond perovskites, this work can guide a highly predictive characterization of any emerging semiconductor for photovoltaic or photoelectrochemical energy conversion. A best practice for the interpretation of terahertz and microwave measurements on photovoltaic materials is presented.

Room temperature NO2 gas sensor based on stain-etched porous silicon: Towards a low-cost gas sensor integrated on silicon

In this work, we investigate the use of a new low-cost gas sensor based on porous silicon to detect low concentration of NO2 at room temperature. In this work, we focused on the gas sensing properties of two different types of porous silicon (PS) prepared by a simple chemical method namely nano-porous silicon (nano-PS) and macro-porous silicon (macro-PS). The prepared sensors are characterized by different pores size, thicknesses and porosity. Electronic properties of the synthesized structures were studied by measuring the effective minority carrier lifetime using a µPCD lifetime tester. Structural properties and morphology of PS samples were also presented using Fourier transforms infrared (FTIR) spectroscopy and scanning electron microscope (SEM). The gas sensing properties of nano-PS and macro-PS were performed at room temperature for NO2 gas. Macro-PS and nano-PS sensors exhibit different behaviors attributed to the difference in their morphologies. The tested sensors exhibit considerable sensitivity at room temperature to low concentration of NO2 (4 ppm) during response time up to 45 s.

Carrier Diffusion in GaN : A Cathodoluminescence Study. II. Ambipolar versus Exciton Diffusion

We determine the diffusion length of excess carriers in $\mathrm{Ga}\mathrm{N}$ by spatially resolved cathodoluminescence spectroscopy utilizing a single quantum well as a carrier collector or carrier sink. Monochromatic intensity profiles across the quantum well are recorded for temperatures between 10 and 300 K. A classical diffusion model accounts for the profiles acquired between 120 and 300 K, while for temperatures lower than 120 K, a quantum capture process has to be taken into account in addition. Combining the diffusion length extracted from these profiles and the effective carrier lifetime measured by time-resolved photoluminescence experiments, we deduce the carrier diffusivity as a function of temperature. The experimental values are found to be close to theoretical ones for the ambipolar diffusivity of free carriers limited only by intrinsic phonon scattering. This agreement is shown to be fortuitous. The high diffusivity at low temperatures instead originates from an increasing participation of excitons in the diffusion process.

Assessment of radiological hazards from soil samples in the Northeastern area of Burkina Faso

The activity concentrations of main naturally occurring radionuclides were determined with the aim of assessing the radiation hazards in the Northeastern part of Burkina Faso. Soil samples were taken and analyzed by the gamma-ray spectrometry method. The ranges of specific activity of 238U, 232Th and40K are 15.25 pm 2.59 , text{Bq} cdot {text{kg}^{-1}} to 109.57 pm 3.21 , text{Bq} cdot {text{kg}^{-1}}, 19.56 pm 1.65 , text{Bq} cdot {text{kg}^{-1}} to 44.88 pm 2.49 text{Bq} cdot {text{kg}^{-1}} and 125.74 pm 4.40 , text{Bq} cdot {text{kg}^{-1}} to 705.85 pm 10.79 , text{Bq} cdot {text{kg}^{-1}} respectively. Three high background radioactivity areas have been identified for Uranium, Thorium and Potassium on different places in the study area. The radiological hazards indices vary from 62.87 , text{Bq} cdot {text{kg}^{-1}} to 189.47 , text{Bq} cdot {text{kg}^{-1}} for the Radium equivalent activity (Ra_{eq}), 29.5 , eta text{Gy} cdot {text{h}^{-1}} to 86.65 , eta text{Gy} cdot {text{h}^{-1}} for the absorbed dose rate (D_R), 0.18 , text{mSv} cdot {text{y}^{-1}} to 0.53 , text{mSv} cdot {text{y}^{-1}} for the annual effective dose rate (AEDE), 0.21 to 0.81 for the internal hazard index (H_{in}), 0.17 to 0.51 for the external hazard index (H_{ex}), 1.27 times 10^{-4} to 3.73 times 10^{-4} for the Excess Lifetime Cancer Risk (ELCR) and 209.01{mkern 1mu} mu , 0.18{mkern 1mu} Sv cdot y^{{ - 1}} to 594.21 , mu text{Sv} cdot {text{y}^{-1}} for the annual gonadal dose equivalent. The average values of indices are well below their permissible limit. However, at Niapsi the obtained values for absorbed dose rate, annual effective dose rate and excess lifetime cancer risk are little above their permissible limit.

Measurement of the Bs0→μ+μ− decay properties and search for the B0→μ+μ− and Bs0→μ+μ−γ decays

An improved measurement of the decay Bs0→μ+μ− and searches for the decays B0→μ+μ− and Bs0→μ+μ−γ are performed at the LHCb experiment using data collected in proton-proton collisions at s=7, 8 and 13 TeV, corresponding to integrated luminosities of 1, 2 and 6 fb−1, respectively. The Bs0→μ+μ− branching fraction and effective lifetime are measured to be B(Bs0→μ+μ−)=(3.09−0.43−0.11+0.46+0.15)×10−9 and τ(Bs0→μ+μ−)=(2.07±0.29±0.03) ps, respectively, where the uncertainties include both statistical and systematic contributions. No significant signal for B0→μ+μ− and Bs0→μ+μ−γ decays is found and the upper limits B(B0→μ+μ−)<2.6×10−10 and B(Bs0→μ+μ−γ)<2.0×10−9 at 95% confidence level are determined, where the latter is limited to the range mμμ>4.9 GeV/c2. Additionally, the ratio between the B0→μ+μ− and Bs0→μ+μ− branching fractions is measured to be Rμ+μ−<0.095 at 95% confidence level. The results are in agreement with the Standard Model predictions.10 MoreReceived 23 August 2021Accepted 8 December 2021DOI:https://doi.org/10.1103/PhysRevD.105.012010Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.© 2022 CERN, for the LHCb CollaborationPhysics Subject Headings (PhySH)Research AreasBranching fractionFlavor changing neutral currentsRare decaysPhysical SystemsBottom mesonsParticles & Fields

Analysis of Neutral B-Meson Decays into Two Muons.

Branching fraction and effective lifetime measurements of the rare decay B_{s}^{0}→μ^{+}μ^{-} and searches for the decays B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ are reported using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13TeV, corresponding to a luminosity of 9 fb^{-1}. The branching fraction B(B_{s}^{0}→μ^{+}μ^{-})=(3.09_{-0.43-0.11}^{+0.46+0.15})×10^{-9} and the effective lifetime τ(B_{s}^{0}→μ^{+}μ^{-})=2.07±0.29±0.03 ps are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ decays is found and upper limits B(B^{0}→μ^{+}μ^{-})<2.6×10^{-10} and B(B_{s}^{0}→μ^{+}μ^{-}γ)<2.0×10^{-9} at the 95%C.L. are determined, where the latter is limited to the range m_{μμ}>4.9 GeV/c^{2}. The results are in agreement with the standard model expectations.

Enhanced Surface Passivation of Subnanometer Silicon Dioxide Films by Superacidic Treatments

Subnanometer-scale silicon dioxide (SiO2) films are frequently present before, during, and after silicon device processing, yet they offer minimal surface passivation and can detrimentally impact subsequent processing steps. Here we develop a process whereby the surface passivation of nanometer and subnanometer SiO2 films is enhanced by up to 2 orders of magnitude by a simple room temperature treatment using the superacid bis(trifluoromethane)sulfonimide (TFSA, sometimes TFSI). By accurately modeling the effective lifetime curves corresponding to the superacid treated SiO2 samples, we have determined that the enhanced passivation is mainly due to a reduction in the interface defect density (Dit) at the Si/SiO2 interface, with a minor contribution also arising from the presence of negative charge. X-ray photoelectron spectroscopy of the treated SiO2 films reveals the presence of fluorine, and this, along with hydrogen, is a strong candidate for the chemical passivation of defects at the Si/SiO2 interface. Post treatment, the SiO2 films show short time scale electronic instability, whereby a degradation and then recovery are observed over a period of 1–10 h which is attributed to variations in the Dit, as determined from our analysis of the injection-dependent lifetime data. Following the instability period, the surface passivation remains relatively stable for days. Nuclear magnetic resonance measurements of superacid-based solutions reveal that electron-donating solvents should be avoided, as they exacerbate surface passivation instabilities. The results presented demonstrate that simple strategies can be used to enhance the passivation properties of ultrathin films greatly, which in the age of nanotechnology could offer benefits to device performance in a range of applications including solar cells and batteries.

Optimization of Silicon Heterojunction Interface Passivation on p‐ and n‐Type Wafers Using Optical Emission Spectroscopy

To increase the efficiency in p‐type wafer‐based silicon heterojunction (SHJ) technology, one of the most crucial challenges is the achievement of excellent surface passivation. Herein, chemical passivation techniques known for n‐type technology are successfully applied on p‐type float–zone (FZ) wafers, and wafer surface passivation quality is correlated with parameters from plasma diagnostics, namely crystallization rate and electron temperature indices. It is shown that plasma ignition at higher powers than deposition powers enhances effective minority carrier lifetimes τeff fourfold for p‐ (0.6–2.1 ms) and sixfold for n‐type (0.6–3.2 ms) wafers while giving opportunity to process under lower electron temperature indices during the nucleation phase. A subsequent hydrogen plasma treatment has a further beneficial effect on chemical passivation, leading to high effective minority carrier lifetimes of 4.5 and 3.1 ms, and implies open‐circuit voltages, i‐VOC, of 735 and 720 mV for p‐ and n‐type wafers, respectively. In particular, cell precursors built on p‐type wafers demonstrate excellent surface passivation with τeff and i‐VOC (4.1 ms and 745 mV). Using these process optimizations, SHJ cells on both p‐ and n‐type wafers are fabricated with efficiencies exceeding 21%.

Room Temperature Enhancement of Electronic Materials by Superacid Analogues.

Treatment with the superacid bis(trifluoromethanesulfonyl)amide (sometimes known as TFSA, TFSI, or HNTf2) enhances the properties of a wide range of optoelectronic materials, resulting in longer effective carrier lifetimes and higher photoluminescence quantum yields. We have conducted a multimaterial study treating both crystalline silicon and transition metal dichalcogenide (TMDC) monolayers and few-layer flakes with solutions formed from TFSA and a range of compounds with related chemical structures with different Lewis acidities, in order to elucidate the factors underpinning the TFSA-related class of enhancement treatments. We adopt dichloromethane (DCM) as a common solvent as it provides good results at room temperature and is potentially less hazardous than TFSA-dichloroethane (DCE) heated to ∼100 °C, which has been used previously. Kelvin probe experiments on silicon demonstrate that structurally similar chemicals give passivating films with substantially different charge levels, with the higher levels of charge associated with the presence of CF3SO2 groups resulting in longer effective lifetimes due to an enhancement in field-effect passivation. Treatment with all analogue solutions used results in enhanced photoluminescence in MoS2 and WS2 compared to untreated controls. Importantly we find that MoS2 and WS2 can be enhanced by analogues to TFSA that lack sulfonyl groups, meaning an alternative mechanism to that proposed in computational reports for TFSA enhancement must apply.

Assessment of annual effective dose and excess lifetime cancer risk due to alpha emitters in some grain samples in Kerbala Governorate, Iraq

Assessment of annual effective dose and excess lifetime cancer risk due to alpha emitters in some grain samples in Kerbala Governorate, Iraq

Scintillation and optical properties of xenon-doped liquid argon

Liquid argon (LAr) is a common choice as detection medium in particle physics and rare-event searches. Challenges of LAr scintillation light detection include its short emission wavelength, long scintillation time and short attenuation length. The addition of small amounts of xenon to LAr is known to improve the scintillation and optical properties. We present a characterization campaign on xenon-doped liquid argon (XeDLAr) with target xenon concentrations ranging from 0 to 300 ppm by mass encompassing the measurement of the photoelectron yield Y, effective triplet lifetime τ 3 and effective attenuation length λ att. The measurements were conducted in the Subterranean Cryogenic ARgon Facility, Scarf, a 1 t (XeD)LAr test stand in the shallow underground laboratory (UGL) of TU-Munich. These three scintillation and optical parameters were observed simultaneously with a single setup, the Legend Liquid Argon Monitoring Apparatus, Llama. The actual xenon concentrations in the liquid and gaseous phases were determined with the Impurity DEtector For Investigation of Xenon, Idefix, a mass spectrometer setup, and successful doping was confirmed. At the highest dopant concentration we find a doubling of Y, a tenfold reduction of τ 3 to ∼90 ns and a tenfold increase of λ att to over 6 m.

Соотношение радиационно-обусловленных потенциальных канцерогенных рисков ОЯТ реактора ВВЭР-1000 и РАО реактора БРЕСТ-1200 при выработке 1 ГВт х год электроэнергии. Часть 2. Радиологическая миграционная эквивалентность

Currently it is acknowledged that the problem of disposal of radioactive waste (RW) from the nu-clear reactors largely depends on the use of fast neutron reactors (fast reactors) in nuclear power industry. These reactors are able to burn and transmutate long-lived radionuclides in closed nu-clear fuel cycle (NFC). In an open NFC with thermal neutron reactors (thermal reactors), unpro-cessed spent nuclear fuel (SNF) is buried. In a closed NFC with fast reactors the reprocessed SNF is disposed. In this paper, the feasibility and possibility of closing the NFC in a two-component nuclear power industry with thermal and fast reactors are studied. Potential biological hazard (PBH) to the public from unprocessed SNF from the thermal reactor WWER-1000 and re-processed SNF from the fast reactor BR-1200, were evaluated with account of relevant radionu-clides migration from the deep disposal to the earth surface. PBH values were expressed in terms of committed effective dose and lifetime attributable risk (LAR) of malignant neoplasms, normalized to 1 GW of generated electricity. PBH of RW from BR-1200 is about 100 times lower than risk from unprocessed SNF from WWER-1000. Comparative evaluation of PBH from BR-1200 and unprocessed SNF from WWER-1000 demonstrated that the committed effective doses from the dwell-water used by the public from the time of radionuclides appearance at the earth surface are 0.7 µSv and 80 µSv/year respectively, and LAR values are 6∙10-9 and 7.74∙10-6 re-spectively. At the same time, PBH of reprocessed SNF from WWER-1000, from the time of radio-nuclides appearance on the earth’s surface is an order less than PBH of RW from BR-1200. In accordance with the principle of radiological equivalence of RW disposal, it was established that the RW from BR-1200 satisfies the time limit for achievement of the equality with the PBH of the equivalent mass of uranium raw material will be within the range of 300 years. If PBH is ex-pressed in terms of LAR the radiological migration equivalence is achieved even earlier. Thus, when reprocessing SNF from thermal reactors and operating thermal reactors with simultaneous construction and operation of fast reactors (in a two-component nuclear power industry), it is ad-visable to use a closed NFC and dispose of RW, considering the principle of radiation-migration equivalence.

Coupled thermal and structural analysis of disc brake rotor with varying angle of rotation of ventilation holes

The automobile’s speed and torque requirements are growing all the time these days. As we all know, not only are speed and torque are a necessity of automotive manufacturers, but also braking without sliding and vehicle comfort is also a fundamental element. The major goal of this project is to study the impact of inclined holes on the disc brake rotor similar to that of Suzuki GSXR 1100 which will decrease overall deformation and maximize heat dissipation. AUTODESK FUSION 360 is used to create various forms of vented holes in a brake disc rotor. The inner and outer boundaries are retained, with changes occurring only in the intermediate patterns/regions between them, giving the models similar structural boundary limitations. ANSYS, a finite element software for calculating the temperature distribution, fluctuation of stresses and deformation throughout the disc brake profile, is utilized for the static structural analysis and steady-state thermal analysis of the brake disc rotor. To improve the quality of the results a coupled static structural and thermal analysis simulation was performed which showed a linear decline of temperature and total deformation with an increase in the angle of the holes. Thus, the effective lifetime of the disc brake rotor will be increased. Based upon the values of von-misses stresses, deformation, temperature, total heat flow obtained via ANSYS simulation, the best design changes in the brake disc rotor are proposed.

English

In this manuscript, we present a study on the effects of magnetic field on charge carrier effective lifetime within the base of a polycrystalline PV solar cell p-n junction. This study is elaborated in two forms as a theoretical study and an experimental study. Indeed, under various magnetic field values, PV solar cell is illuminated by using the light from stroboscopic. From a theoretical approach mainly use the open circuit voltage decay method.&nbsp; Green&rsquo;s functions and boundaries conditions are used to solve charge carrier&rsquo;s diffusion equation. Open circuit transient voltage decay expression is found. The charge carriers&rsquo; effective lifetime values inversely proportional to the slope of open circuit voltage decay curve are deducted. A simple experimental set-up used open circuit voltage decay method mainly, these experimental measurements of charge carriers&rsquo; effective lifetime are done and the effects of magnetic field are then outlined. Globally, magnetic effects on effective charge carrier lifetime are then analyzed. These two types of results obtained present qualitatively the decay of charge carriers&rsquo; effective lifetime when magnetic field increase. In the first time, theoretical results and experimental results are in good agreement and in the second time these results are in good agreement with literature results. Key words: Effective lifetime, open circuit voltage decay, magnetic field.